1. Field of the Invention
The invention relates to a substrate processing apparatus which performs processing such as cleaning on various types of substrates such as semiconductor wafers, glass substrates for photomask, glass substrates for liquid crystal display, glass substrates for plasma display and optical disk substrates by supplying a processing liquid to these substrates.
2. Description of the Related Art
Conventional substrate processing apparatuses of this type include a substrate processing apparatus in which a substrate such as a semiconductor wafer is supported on a disk-shaped rotary base member which is supported such that the rotary base member can freely rotate about a vertical axis, a processing liquid such as a chemical solution is supplied to the top and the bottom surfaces of the substrate while rotating the substrate, and the substrate is consequently processed (Japanese Patent Application Laid-Open Gazette No. H11-176795). In the substrate processing apparatus described in Japanese Patent Application Laid-Open Gazette No. H11-176795, a plurality of, three for instance, holding members such as chuck pins, which are disposed in the vicinity of the outer edge of the rotary base member, position and support a substrate. This realizes transmission of rotation force from the rotary base member to the substrate, and rotates the substrate while restricting the substrate in the horizontal direction. As the substrate rotates while the processing liquid is supplied to the center of the top and the bottom surfaces of the substrate, the processing liquid spreads toward outside to the substrate, and the top and the bottom surfaces of the substrate are accordingly processed. The processing liquid splashing at the rim of the substrate may hit and jump at an anti-splashing cup or the like which is disposed around the rotary base member and adhere again to the substrate. To prevent this, a blocking member is disposed near the top surface of the substrate, thereby restricting the space on the top side of the substrate, and inert gas such as nitrogen gas is introduced to thus restricted space. Meanwhile, similarly as for the bottom side of the substrate, inert gas is introduced to the space which is created between the rotary base member which serves as the blocking member and the bottom surface of the substrate, for prevention of re-adhering of the processing liquid to the bottom surface of the substrate.